Door assembly with shear layer control aperture

ABSTRACT

There is described a vehicle door assembly with shear layer control for controlling the airflow in and around an aperture in the vehicle fuselage. The vehicle door assembly consists of an upper door and a lower door, both slidably mounted to the exterior surface of the vehicle fuselage. In addition, an inner door is slidably mounted beneath the upper door. Beneath the inner door is an aperture assembly having an aperture opening positionable to be substantially flush with the exterior surface of the vehicle fuselage. Also provided are means for positioning the aperture assembly in an upward and downward direction in relation to the vehicle fuselage.

The invention described herein was made in the performance of work underNASA Contract No. NAS2-13599 and is subject to the provisions of Section305 of the National Aeronautics and Space Act of 1958(42 U.S.C. 2457).

BACKGROUND OF THE INVENTION

For a variety of applications, both scientific and otherwise, it hasbecome desirable to include open-air apertures in the fuselages ofaircraft or other airborne vehicles. One such application is theinstallation and operation of optical and sonic equipment for theobservation of atmospheric and extra-atmospheric phenomena. Moreover,optical and other scientific equipment positioned to take advantage ofan aperture positioned in the fuselage of an aircraft are extremelysensitive, and turbulent airflow in and around the aperture prevents orimpairs use of such equipment.

Many scientific applications would benefit from the ability to positionhighly sensitive scientific equipment within the fuselage of an aircraftor other airborne vehicles and utilizing an open air aperture. When thescientific equipment is in use, the aperture can be fully revealed. Whenthe scientific equipment is not in use, the ability to close theaperture serves as a means to protect and maintain a conditionedenvironment for the instruments.

For the foregoing and other reasons, there is a need for a door assemblycapable of being mechanically positioned either to open or close anaperture in the fuselage of an aircraft or other airborne vehicles withan integral shear layer control.

This invention relates to a door assembly capable of being mechanicallypositioned either to open or close a shear layer control aperture in thefuselage of an aircraft or other vehicle. The exterior surface of thedoor assembly is a shear layer control surface for providing anoptically and acoustically stable shear layer over the aperture.

SUMMARY OF THE INVENTION

The present invention satisfies the foregoing and other needs byproviding a door assembly including a shear layer control aperturemounted over a large aperture in the exterior of an aircraft or otherairborne vehicle fuselages. The door assembly includes an upper door, alower door, an inner door, and an aperture assembly. The upper and lowerdoors are slidably mounted to external fuselage-mounted tracksconcentric with the exterior surface of an aircraft or other vehiclefuselage. The upper door, used to close the upper portion of theaperture during operation, is fixed to the aperture assembly on one endand moves freely along external fuselage-mounted tracks. The lower door,similar in operation to the upper door, is utilized to close the lowerportion of the aperture during operation. On a concentric axisimmediately below the upper and lower doors there is provided anaperture assembly positioned on tracks mounted internal to the fuselage,the aperture assembly being flush with the exterior surface of thevehicle fuselage. An inner door used to open and close the apertureassembly is mounted on one end to rails on the interior surface of theupper door and on another end to grooves on the exterior side of theaperture assembly. Racks on the interior surface of the inner doorengage pinion gears on the exterior surface of the aperture assembly;activation of the pinion gears allowing the inner door to cover oruncover the aperture assembly.

The door assembly of the present invention is powered by a drive motormounted on the aperture assembly driving parallel shafts through acommon transmission. One of the shafts opens and closes the aperture bydriving the pinion gears mounted on the exterior surface of the apertureassembly which, in turn, engage racks on the interior surface of theinner door. The other shaft operates pinion gears that drive theaperture assembly upward and downward along the pair of fuselage-mountedracks. The outer doors are utilized to close the opening of the vehiclefuselage vacated as the aperture assembly tracks up and down.

The exterior surface of the aperture assembly provides a shear layercontrol surface controlling airflow over an opening and controlling theflow along the vehicle fuselage.

The door assembly of the present invention provides effective shearlayer control, substantially non-turbulent cavity environment, withminimum drag. Moreover, the design is easy to fabricate, assemble,install and service. Other advantages and applications deriving from theuse of the invention will readily suggest themselves to those skilled inthe art.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following detaileddescription taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of the present invention installed on anaircraft having an exposed aperture;

FIG. 2 is a perspective view of the embodiment shown in FIG. 1 with theaperture closed;

FIG. 3 is a perspective view of the embodiment shown in FIG. 1 with theaperture open;

FIG. 4 is a perspective view of the exterior of the inner door of theaperture assembly;

FIG. 5 is a perspective view of the interior of the inner door of theaperture assembly;

FIG. 6 is an illustration of the drive assembly;

FIG. 7 is a perspective view of the portion of the aircraft fuselagecontaining the opening used by the aircraft door assembly;

FIG. 8 is a perspective view of the interior of the door assembly; and

FIG. 9 is an interior view of the upper door.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to FIG. 1, there is illustrated a perspective view of thedoor assembly 2 with aperture 36 in its "open" position, as installed inan aircraft. In flight, the normal airstream flow across aperture 36 isin the direction indicated by arrows 38 and 40. Without the benefit ofthe shear layer recovery surface 16 on the downstream edge 42 of theexterior side of aperture 36, substantial turbulence would result in andaround aperture 36, thereby adversely affecting the operation of opticaland other scientific equipment.

Referring now to FIGS. 2 and 3, there is shown an exterior view of thedoor assembly 2 as mounted to the fuselage 1. The door assembly 2includes an inner door 8, an upper door 4, a lower door 6, and anaperture assembly 14. The inner door 8 is positioned between the upperdoor 4 and lower door 6, and is slidably mounted to rails 32 (FIG. 9) onthe interior surface of upper door 4 on one end, and to an inner doortrack 22 on the side of aperture assembly 14 on the other end. Asillustrated in FIG. 2, the inner door 8 is in its "down" position,concealing the aperture assembly 14 which lies beneath. When moved inthe direction of the arrow 9 (FIG. 2), the inner door 8 rolls behindupper door 4 such that when lip 7 abuts the edge of upper door 4, innerdoor 8 is completely concealed behind upper door 4 and is said to be inits "up" position, as depicted in FIG. 3. With the inner door in its"up" position, the aperture assembly 14 is revealed and is said to be"open."

The entire door assembly 2 is slidably mounted to external tracks 11 and15 (FIG. 7) to allow the upper door 4, the inner door 8, the lower door6 and the aperture assembly 14 to move in an upward and downwarddirection in unison. The lower door 6 slides on tracks 15 to close theopening in fuselage 1 as door assembly 2 moves in an upward and downwarddirection. The lower door 6 is connected with the aperture assembly 14on one end, and moves freely in an upward and downward direction ontracks 15 on the other end. Similarly, upper door 4 is connected toaperture assembly 14 on one end while moving freely in an apward anddownward direction on tracks 11 on the other end for the same purpose.The ability to move in unison allows the door assembly 2 to have a rangeof motion for positioning the aperture assembly 14.

Referring to FIG. 7, there is shown a portion of the fuselage 1 of anaircraft or other vehicle containing aperture 17. Tracks 11 are mountedto the fuselage 1 above aperture 17, while tracks 15 are mounted to thefuselage 1 below aperture 17. Mounted to the fuselage 1 within theinterior compartment are rack gears 21 and guides 25. Rack gears 21engage aperture assembly drive pinion gears 20 (FIG. 5) to provide ameans for driving the aperture assembly 14 upward and downward withinaperture 17. Guides 25 engage follower wheels 24 (FIG. 5) of theaperture assembly 14 to provide a means for support for the apertureassembly 14 as it travels upward and downward when driven by driveassembly 52 (FIG. 6).

Referring now to FIG. 4, there is illustrated an exterior view of theaperture assembly 14. The aperture assembly 14 defines an aperture 36.Inner door pinions 18 engage racks 34 (FIG. 8) on the interior surfaceof the inner door 8. Inner door tracks 22 (only one shown in FIG. 4) arelocated on both the upstream and downstream sides of the apertureassembly 14 and through which lip 7 (FIG. 2) of the inner door 8 travelswhen the inner door 8 is moved in an upward or downward direction. Theupstream edge 46 of aperture 36 is at nearly continuous ninety degreeangles from any tangential point selected along the upstream edge 46 ofthe exterior surface of the aperture assembly 14. Intersecting theupstream edge 46 is shear layer recovery surface 16. Shear layerrecovery surface 16 is a curved structure curving down into the vehiclecavity and is convexly shaped in relation to the airstream. The shearlayer recovery surface 16 provides a reattachment for the airstreamdetached at upstream edge 46 of aperture 36 and promotes smoothreattachment of the airstream to the external surface of the vehicle. Asthe airstream passes in the direction depicted by arrows 38 and 40 (FIG.1), the airstream detaches from the aperture assembly 14 at the upstreamedge 46 of aperture 36 and then travels over the aperture 36 toward theinterior of the vehicle cavity. Smooth shear layer flow over aperture 36is provided by the shear layer recovery surface 16 catching theairstream as it reattaches on the downstream edge 42 of aperture 36 andreattaching the airstream from the aperture 36 to the downstream vehiclesurface.

Referring now to FIG. 5, there is illustrated an interior view of theaperture assembly 14. Aperture assembly 14 mounts flush with theexterior surface of aircraft fuselage 1 on fuselage-mounted rack gears21 (FIG. 7). As a drive motor 28 drives shaft 30 so as to rotateaperture assembly drive pinion gears 20, the gears engage thefuselage-mounted rack gears 21 (FIG. 7) to drive the aperture assembly14 upward or downward. Follower wheels 24 are provided at the bottom ofthe interior surface of the aperture assembly 14 to engage guides 25 toassist the aperture assembly 14 as it travels along the fuselage-mountedrack gears 21 as the aperture assembly 14 is driven upwardly anddownwardly by the drive assembly 52 (FIG. 6).

Referring now to FIG. 6, there is illustrated the drive assembly 52which operates to both open and close the aperture 36, and to drive theaperture assembly 14 on fuselage-mounted rack gears 21 (FIG. 7). Thedrive assembly 52 is mounted on the interior surface of the apertureassembly 14 (FIG. 5), and includes the drive motor 28 driving parallelshafts 30 and 54 through a common transmission 26. Shaft 54 drives innerdoor pinion gears 18 (FIG. 5) mounted on the exterior surface of theaperture assembly 14. The inner door pinion gears 18, in turn, engageracks 34 (FIG. 8) on the interior surface of the inner door 8 forrevealing or concealing the aperture 36 with the inner door 8. Shaft 30drives aperture assembly drive pinion gears 20, while the pinion gears,in turn, engage fuselage-mounted rack gears 21 (FIG. 7) for driving theaperture assembly 14 in an upward or downward direction.

Referring now to FIG. 8, there is illustrated an interior view of theentire door assembly of the present invention. Mounted to the vehiclefuselage are tracks 11 and 15 shown as integrated with the entire doorassembly. Lower door 6 is slidably mounted to tracks 15, while upperdoor 4 is slidably mounted to track 11. Inner door 8 is depictedpartially open, revealing only a portion of aperture 36. On the interiorsurface of inner door 8 are rack gears 34 which engage pinion gears 18(FIG. 4) on the exterior surface of aperture assembly 14 for the purposeof moving the inner door upward and downward to open or close theaperture 36. The aperture assembly 14 itself is shown with pinion gears20 engaging fuselage-mounted rack gears 21 and with follower wheels 24engaging fuselage-mounted guides 25. Drive assembly 52 (FIG. 6) causespinion gears 20 to turn against rack gears 21, which in turn causesupward and downward movement of aperture assembly 14. With followerwheels 24 engaged by guides 25, smooth and stable support is providedthe lower portion of aperture assembly 14 as it travels in an upward anddownward direction. Moreover, the positioning of the fuselage-mountedrack gears 21 and guides 25 ensure that the exterior surface of apertureassembly 14 is flush with the exterior surface of the vehicle fuselage.It is important that the exterior surfaces of the aperture assembly 14and the vehicle fuselage be flush in order for the shear layer controlsurface of aperture assembly 14 to be effective.

Referring now to FIG. 9, there is illustrated an interior view of theupper door 4. Spaced across the interior surface are internal rails 32engaging the inner door rails 12 (FIG. 2) and guiding the inner door 8as it travels beneath the upper door 4.

Although the preferred embodiment of the invention has been illustratedin the accompanying drawings and described in the foregoing DetailedDescription, it will be understood that the invention is not limited tothe embodiment disclosed, but is capable of numerous rearrangements andmodifications of steps without departing from the spirit of theinvention.

We claim:
 1. A door assembly for a vehicle, comprising:an upper doorslidably mounted to a vehicle to selectively close an aperture in thevehicle; a lower door slidably mounted to the vehicle to selectivelyclose the aperture in conjunction with said upper door; an inner doorslidably mounted for movement beneath the upper and lower doors; anaperture assembly slidably mounted to the vehicle to move beneath theinner door and positioned substantially flush with the exterior surfaceof the vehicle, the aperture assembly including an aperture, an interiorsurface and an exterior surface; and means for positioning the apertureassembly with reference to the inner door.
 2. The door assembly of claim1, including tracks mounted to the vehicle, and wherein the upper doorhas a first end and a second end, the first end slaved to the apertureassembly, and the second end movably mounted to said tracks.
 3. The doorassembly of claim 2, wherein the upper door has an internal surface andan external surface, the internal surface including rails for guidingthe inner door adjacent to the upper door.
 4. The door assembly of claim2, including tracks mounted to the vehicle, and wherein the lower doorhas a first end and a second end, the first end slaved to the apertureassembly, and the second end movably mounted to the tracks.
 5. The doorassembly of claim 3, wherein the inner door includes inner door rails,the inner door movably mounted on the rails of the upper door.
 6. Thedoor assembly of claim 1, wherein the exterior surface of the apertureassembly defines a shear layer control surface.
 7. A door assembly for avehicle, comprising:an upper door slidably mounted to the exteriorsurface of the vehicle; a lower door slidably mounted to the exteriorsurface of the vehicle; an inner door having an exterior side and aninterior side, the inner door slidably mounted beneath the upper andlower doors, and above the exterior surface of the vehicle, the innerdoor further positioned so as to be concealed behind the upper door whenpositioned beneath the upper door; an aperture assembly slidably mountedto the vehicle to move beneath the inner door and positionedsubstantially flush with the exterior surface of the vehicle, theaperture assembly including an aperture, an interior surface and anexterior surface; and means for positioning the aperture assembly in anupward and downward direction in relation to the exterior surface of thevehicle.
 8. The door assembly of claim 7, wherein the vehicle is anaircraft.
 9. The door assembly of claim 7, wherein the exterior surfaceof the aperture assembly defines a shear layer control surface.
 10. Adoor assembly for an aperture of an aircraft, comprising:an apertureassembly mounted to be positioned substantially flush with the exteriorsurface of the aircraft fuselage, the aperture assembly including anaperture opening, an interior surface and an exterior surface; means forpositioning the aperture assembly in an upward and downward direction inrelation to the aircraft fuselage; an upper door slidably mounted to theexterior surface of the aircraft fuselage; a lower door slidably mountedto the exterior surface of the aircraft fuselage; and an inner doorhaving an exterior surface and an interior surface, the inner doorslidably mounted to be positioned beneath the upper and lower doors, andabove the exterior surface of the aircraft fuselage, the inner doormounted to be concealed behind the upper door when positioned behind theupper door.
 11. The door assembly of claim 10, wherein the exteriorsurface side of the aperture assembly defines a shear layer controlsurface.